An insect called the cottony cushion scale has developed a way to produce offspring without a mate. Some females develop with their father's sperm growing into an bundle of male tissue inside the female's body. This tissue can later produce sperm needed for the female to produce baby scales.

This parasitic tissue, genetically identical to the female's father, lives inside the female and fertilizes her eggs internally—rendering the female a hermaphrodite and making her father both the grandfather and father of her offspring, genetically speaking.

Though this new form of reproduction hasn't replaced cottony cushion scale sex, "this parasitic male has taken off like an epidemic in population," said study leader Andy Gardner, an evolutionary theorist at the University of Oxford.

"Once [this trend] gets started, it's going to sweep through the population so all the females carry it. So there's no point for regular males to exist," Gardner added.

If the females begin passing on the parasitic male to their offspring, there may eventually be no more need for "baby boy" cushion scales that grow up and produce sperm and fertilize females, Gardner said.

Self-fertilizing species do not flourish as well as those that reproduce by sex because the genetic variability tends to die out. Gardner clarified that the female insects are not truly hermaphroditic, as much as they are two different individual insects within one body. Link